Food proteins are widely used in formulated foods because of their nutritional value and functional properties, including emulsifying, foaming, gelling, and water-binding capacities. However, their use in other fields, including pharmaceutical applications is still limited since few works have studied the drug-release properties of food protein-based systems (Chen et al. 2006).
In previous studies, it was shown that release properties of protein based-delivery systems are largely influenced by their matrix swelling properties. Peppas et al. (2000) report that according to the Flory-Rhener theory (1943), swelling is dependent on three components: mixing forces, ionic forces, and elastic forces. Mixing forces are dependent on polymer affinity for release media (which could be linked to polymer solubility), ionic forces are dependent on protein charge (the more the protein is charged, the higher the swelling rate) and elastic forces are connected to interactions between polymer chains that oppose to swelling phenomenon: the higher the cross-linking in the system, the lesser the swelling.
Therefore, modulation of one or more of these mechanisms may possibly lead to a control of the rate of release of a drug from a drug-excipient system or achieve targeting to a particular organ (for example: gastro-resistance favoring intestinal release).
An aspect of this invention provides a strategy allowing to slow down one (or more) of these mechanisms in order to provide a controlled-release system of a protein-based compressed 3-dimensional system or matrix, such as, for example, a tablet.